US4547807A - CCD Imager - Google Patents

CCD Imager Download PDF

Info

Publication number
US4547807A
US4547807A US06/673,252 US67325284A US4547807A US 4547807 A US4547807 A US 4547807A US 67325284 A US67325284 A US 67325284A US 4547807 A US4547807 A US 4547807A
Authority
US
United States
Prior art keywords
signal
ccd
horizontal line
masked
smear
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US06/673,252
Other languages
English (en)
Inventor
Nobuhiro Mitani
Toshihiro Furusawa
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Sanyo Electric Co Ltd
Original Assignee
Sanyo Electric Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Sanyo Electric Co Ltd filed Critical Sanyo Electric Co Ltd
Assigned to SANYO ELECTRIC CO., LTD. reassignment SANYO ELECTRIC CO., LTD. ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: FURUSAWA, TOSHIHIRO, MITANI, NOBUHIRO
Application granted granted Critical
Publication of US4547807A publication Critical patent/US4547807A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N25/00—Circuitry of solid-state image sensors [SSIS]; Control thereof
    • H04N25/60—Noise processing, e.g. detecting, correcting, reducing or removing noise
    • H04N25/62—Detection or reduction of noise due to excess charges produced by the exposure, e.g. smear, blooming, ghost image, crosstalk or leakage between pixels
    • H04N25/621—Detection or reduction of noise due to excess charges produced by the exposure, e.g. smear, blooming, ghost image, crosstalk or leakage between pixels for the control of blooming
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N25/00—Circuitry of solid-state image sensors [SSIS]; Control thereof
    • H04N25/60—Noise processing, e.g. detecting, correcting, reducing or removing noise
    • H04N25/62—Detection or reduction of noise due to excess charges produced by the exposure, e.g. smear, blooming, ghost image, crosstalk or leakage between pixels
    • H04N25/625—Detection or reduction of noise due to excess charges produced by the exposure, e.g. smear, blooming, ghost image, crosstalk or leakage between pixels for the control of smear

Definitions

  • the present invention relates to an imager employing CCD (charge-coupled device) and, more particularly, to an improvement in reducing a smear on a reproducing image.
  • CCD charge-coupled device
  • Such a solid state imager is defined by a plurality of photoelectric transducers aligned in two directions orthogonal to each other.
  • each photoelectric transducers stores a charge which is in relation to the intensity of the impinged light thereon, thereby forming a charge pattern of one field.
  • the charge pattern is transferred to a register, from which a charge signal is read out serially.
  • a bright portion such as a bright spot light
  • an extra charge will be added, during the transfer of the charged pattern, to the photoelectric transducers on which the bright spot light is traced. Such an extra charge will result in an unpleasant smear in the reproduced image.
  • FIG. 1 One arrangement according to the prior art CCD imager is shown in FIG. 1, and which includes a frame transfer type CCD 1 having first register 11, second register 12, and readout resistor 13.
  • first register 11 defining an imaging area
  • photoelectric transducers P' in the bottom row are masked and the other photoelectric transducers P are provided to receive light image.
  • Second register 12 defining a storage area and readout register 13 are also masked.
  • an image integration period for example, 16.1 milliseconds
  • an image transfer period for example, 0.5 millisecond
  • first register 11 Before the first integration period starts, a "field" with no image information appears in first register 11 as if a "field” is pulled down across first register 11 in a blind pull down manner.
  • First register 11 receives light even during the "field” is pulled down.
  • the photoelectric transducers P' in the last row H' carry a signal obtained by the quick scan of the new field vertically across the light receiving area.
  • the signal in the last row H' is so low that it can be disregarded.
  • a photoelectric trandsducer will be integrated to a small degree even during the field scans across that bright spot.
  • the charge distribution along line Lm shown in FIG. 3a which extends through the masked last row H' has a small mount as indicated in graph G Lm . Since such a small mount appears on, and added to, every horizontal line a vertical smear will appear in that field. Thus, the signal shown in graph G Lm is called a smear signal.
  • photoelectric transducers P are integrated, each charged to a level relative to the brightness of the received light. Accordingly, the received image is changed to a charge pattern on photoelectric transducers P.
  • the charge distribution along line L1 shown in FIG. 3a which intersects the spot image is indicated in graph G L1 .
  • the charge signals which have accumulated one "field" are transferred, in parallel, in the column direction from register 11 to resistor 12, such that the charge in the photoelectric transducers P in the first row from the top are transferred to those in the second row, and so on.
  • a next new field appears in first register 11 as the same manner described above in the blind pull down manner.
  • the charge pattern is formed in the same manner described above, and at the same time, the signals stored in the second register 12 are readout through the readout register 13 serially such that the first readout line signal, which is the smear signal carried in the last row H' in photoelectric transducers P', is transferred and stored in line memory 2.
  • switch S changes its connection from the condition shown in FIG. 1 to such that terminal Ta is connected to terminal Tc and terminal Td is connected to terminal Tf.
  • the readout signal through terminals Ta and Tc and the smear signal from line memory 2 are transferred at the same time to subtracter 3 at which readout signal is subtracted by smear signal.
  • the subtracted result such as indicated in graph G L1-Lm , is produced from the subtracter 3.
  • FIG. 2 diagrammatically illustrates an arrangement of overflow drain 14 interleaving the aligned photoelectric transducers P.
  • overflow drain 14 When a very bright image is impinged, photoelectric transducers generate much more charge signal than can be stored at that location. The excess charge tends to spread to the adjacent locations along the chargecoupled channel, resulting as "blooming" of the image. But when overflow drain 14 is provided, the excess charge, which is above a predetermined level Vmax, flows through the overflow drain 14, thereby eliminating undesirable blooming.
  • the present invention has been developed with a view to substantially solving the above described problem and has for its essential object to provide an improved CCD imager which can reduce the smear and, at the same time, which can reduce the blooming around a bright image without producing any dark portion at the center of the bright image.
  • a CCD imager comprises a CCD having a plurality of photoelectric transducers aligned vertically and horizontally, with at least one horizontal line being masked.
  • the CCD produces unmasked horizontal line signals obtained from the unmasked horizontal lines and masked horizontal line signal obtained from the masked horizontal line.
  • a line memory coupled to the CCD stores the masked horizontal line signal and produces the masked horizontal line signal repeatedly and serially.
  • a subtracter is connected to the line memory for subtracting the masked horizontal line signal from each unmasked horizontal line signal and for producing a subtracted signal.
  • a comparator is provided for comparing the unmasked horizontal line signal with a threshold voltage obtained from a constant voltage source and for producing a first signal when the unmasked horizontal line signal is below the threshold voltage, and a second signal when the same is above the threshold voltage.
  • a switch means is coupled to the comparator for permitting the subtracted signal to pass therethrough when the first signal is produced, and for permitting the unmasked horizontal line signal to pass therethrough when the second signal is produced.
  • FIG. 1 is a circuit diagram of a CCD imager according to the prior art
  • FIG. 2 is a diagrammatic view of an array of photoelectric transducers in the CCD provided with an overflow drain;
  • FIG. 3a is a diagrammatic view showing a vertical smear appearing on a reproduced image of a bright spot, and also showing graphs of charge distribution along particular lines L1 and Lm, and a produced video signal;
  • FIG. 3b is a diagrammatic view showing a reproduced image with the smear being removed
  • FIG. 4a is a diagrammatic view showing a vertical smear appearing on a reproduced image of a very bright spot, and also showing graphs of charge distribution along particular lines L1 and Lm, and a produced video signal;
  • FIG. 4b is a diagrammatic view showing a reproduced image with the smear being removed, but having unwanted dark portion within the bright portion;
  • FIG. 5 is a circuit diagram of a CCD imager according to the present invention.
  • FIG. 6 is a circuit diagram of a switch arrangement shown in FIG. 5;
  • FIG. 7a is a diagrammatic view showing a vertical smears appearing on a reproduced image of very bright spots, and also showing graphs of charge distribution along particular lines L1, L2 and Lm, and a produced video signal;
  • FIG. 7b is a diagrammatic view showing a reproduced image with the smear being removed without any unwanted dark portion within the bright portion.
  • FIG. 5 a CCD imager according to the present invention is shown.
  • the imager according to the present invention further has a comparator 4 coupled with a constant voltage source 5 and a switch S2.
  • the CCD imager of FIG. 5 has an overflow drain, such as 14 shown in FIG. 2, or the like, which prevents the blooming.
  • Switch S2 has terminals Tg, Th and Ti in which Th is connected to terminal Tc of switch S1, Ti is connected to subtracter 3, and Tg is an output which is either connected to terminal Th or Ti.
  • the switch S2 is controlled by the output signal from comparator 4.
  • Comparator 4 has its one input connected to terminal Tc of switch S1 for receiving readout signal from CCD 1 when switch S1 connects its terminals Ta and Tc. Another input of comparator 4 is connected to constant voltage source 5 for receiving a threshold voltage Vth, which is a little below the voltage Vmax of the overflow drain. The output of comparator 4 is connected to switch S2.
  • comparator 4 When the readout signal from CCD 1 as obtained from terminal Tc is smaller than the threshold level Vth, that is when the image corresponding to that signal has a brightness below a certain level, such as shown by round-top mountains in graphs G L1 and G L2 in FIG. 7a, comparator 4 produces a signal for effecting switch S2 to connect its terminal Ti with terminal Tg, thereby producing a subtracted video signal from output terminal Tg. Accordingly, a video signal without smear is produced from terminal Tg.
  • comparator 4 when the readout signal from CCD 1 as obtained from terminal Tc is greater than that of the threshold level Vth, that is when the image corresponding to that signal has a brightness above a certain level, such as shown by flat-top mountains in graphs G L1 and G L2 in FIG. 7a, comparator 4 produces a signal for effecting switch S2 to connect its terminal Th with terminal Tg, thereby producing a video signal without being subtracted from output terminal Tg. Accordingly, an image having no undesirable dark spot within the bright area can be reproduced.
  • graphs G L1 , G L2 and G Lm show video signals obtained along lines L1, L2 and Lm, respectively, before the unwanted smear signals are removed.
  • the signal shown by graph G L1 is processed in the circuit of FIG. 5, it is changed to the signal shown by graph G L1 ' in which the round-top mountain is eliminated, but no change in the flat-top mountain.
  • a similar change is seen in the signal shown by graph G L2 .
  • the reproduced image has no smear and no dark spot within the bright area, as shown in FIG. 7b.
  • switch S2 is shown, which is formed by a logic circuit.
  • Terminal Ti is connected to analog switch AS1.
  • terminal Th is connected to analog switch AS2.
  • the outputs of analog switches AS1 and AS2 are connected to each other and further to output terminal Tg.
  • a line from comparator 4 is connected to inverter IN1 which is connected to another inverter IN2 and also to a control terminal of analog switch AS2.
  • the output of inverter IN2 is connected to a control terminal of analog switch AS1.
  • Comparator 4 in combination with switch S2 of FIG. 6 is designed to operate such that when the readout signal from CCD 1 as obtained from terminal Tc is smaller than the threshold level Vth, that is when the image corresponding to that signal has a brightness below a certain level, comparator 4 produces a HIGH signal.
  • inverter IN1 produces a LOW signal to brake analog switch AS2, and inverter IN2 produces a HIGH signal to make analog switch AS1.
  • subtracted video signal is transmitted through terminal Ti, analog switch AS1 to output terminal Tg.
  • comparator 4 when the readout signal from CCD 1 as obtained from terminal Tc is greater than that of the threshold level Vth, that is when the image corresponding to that signal has a brightness above a certain level, comparator 4 produces a LOW signal.
  • inverter IN1 produces a HIGH signal to make analog switch AS2, and inverter IN2 produces LOW to brake analog switch AS1.
  • a video signal without being subtracted is produced from output terminal Tg.
  • the signals applied to circuits 2, 3, 4 and 5 shown in FIG. 5 can be processed in a digital form.
  • an analog-to-digital converter 20 is inserted between CCD 1 and switch S1, and a digital-to-analog converter 21 is connected after output terminal Tg, as indicated in FIG. 5.

Landscapes

  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Transforming Light Signals Into Electric Signals (AREA)
US06/673,252 1983-11-22 1984-11-20 CCD Imager Expired - Lifetime US4547807A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP58219784A JPS60112376A (ja) 1983-11-22 1983-11-22 撮像装置
JP58-219784 1983-11-22

Publications (1)

Publication Number Publication Date
US4547807A true US4547807A (en) 1985-10-15

Family

ID=16740951

Family Applications (1)

Application Number Title Priority Date Filing Date
US06/673,252 Expired - Lifetime US4547807A (en) 1983-11-22 1984-11-20 CCD Imager

Country Status (4)

Country Link
US (1) US4547807A (enrdf_load_stackoverflow)
JP (1) JPS60112376A (enrdf_load_stackoverflow)
DE (1) DE3442647A1 (enrdf_load_stackoverflow)
GB (1) GB2151105B (enrdf_load_stackoverflow)

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4608608A (en) * 1983-11-30 1986-08-26 Hitachi, Ltd. Solid-state imaging system with smear suppression circuits
US4803554A (en) * 1987-09-30 1989-02-07 Polaroid Corporation Electronic imaging camera utilizing EPROM memory
US4819075A (en) * 1986-09-24 1989-04-04 Hitachi, Ltd. Solid state imaging apparatus with means for controlling signal accumulation period
US4843473A (en) * 1988-03-21 1989-06-27 Polaroid Corporation Charge injection device with low noise readout
US5089894A (en) * 1989-05-15 1992-02-18 Sanyo Electric Co., Ltd. Solid image pickup apparatus for eliminating smear
US5485205A (en) * 1991-06-21 1996-01-16 Sony Corporation Smear compensation circuit for a solid state imager
US20050280724A1 (en) * 2003-12-03 2005-12-22 Sanyo Electric Co., Ltd. Image signal-processing device, method for processing image signal, image signal-processing program product, control device for solid image capturing element, and method for controlling solid image capturing element
WO2006123828A1 (en) * 2005-05-19 2006-11-23 Casio Computer Co., Ltd. Digital camera comprising smear removal function
US20080061216A1 (en) * 2004-07-06 2008-03-13 Matsushita Electric Industrial Co., Ltd. Solid-State Imaging Device
US20080165262A1 (en) * 2006-12-12 2008-07-10 Axis Ab Method for capturing image data
US20090167916A1 (en) * 2007-12-26 2009-07-02 Samsung Techwin Co., Ltd. Imaging apparatus and methods, and storing medium having computer program to perform the methods
US20100014775A1 (en) * 2008-07-16 2010-01-21 Canon Kabushiki Kaisha Image processing apparatus and image processing method

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19538909C1 (de) * 1995-10-19 1996-11-28 Grundig Emv Vorrichtung zur Beseitigung des Smear-Effektes bei CCD-Kameras

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3904818A (en) * 1974-02-28 1975-09-09 Rca Corp Removal of dark current spikes from image sensor output signals
US4010319A (en) * 1975-11-20 1977-03-01 Rca Corporation Smear reduction in ccd imagers
US4490774A (en) * 1983-12-19 1984-12-25 General Electric Company Capacitors containing polyfunctional acrylate polymers as dielectrics

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL8104103A (nl) * 1981-09-04 1983-04-05 Philips Nv Televisie-opneeminrichting voorzien van een vaste-stof beeldopnemer.
JPS59275A (ja) * 1982-06-25 1984-01-05 Sony Corp 固体撮像素子のスミア補正回路

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3904818A (en) * 1974-02-28 1975-09-09 Rca Corp Removal of dark current spikes from image sensor output signals
US4010319A (en) * 1975-11-20 1977-03-01 Rca Corporation Smear reduction in ccd imagers
US4490774A (en) * 1983-12-19 1984-12-25 General Electric Company Capacitors containing polyfunctional acrylate polymers as dielectrics

Cited By (21)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4608608A (en) * 1983-11-30 1986-08-26 Hitachi, Ltd. Solid-state imaging system with smear suppression circuits
US4819075A (en) * 1986-09-24 1989-04-04 Hitachi, Ltd. Solid state imaging apparatus with means for controlling signal accumulation period
US4803554A (en) * 1987-09-30 1989-02-07 Polaroid Corporation Electronic imaging camera utilizing EPROM memory
US4843473A (en) * 1988-03-21 1989-06-27 Polaroid Corporation Charge injection device with low noise readout
US5089894A (en) * 1989-05-15 1992-02-18 Sanyo Electric Co., Ltd. Solid image pickup apparatus for eliminating smear
US5485205A (en) * 1991-06-21 1996-01-16 Sony Corporation Smear compensation circuit for a solid state imager
US20050280724A1 (en) * 2003-12-03 2005-12-22 Sanyo Electric Co., Ltd. Image signal-processing device, method for processing image signal, image signal-processing program product, control device for solid image capturing element, and method for controlling solid image capturing element
US20080061216A1 (en) * 2004-07-06 2008-03-13 Matsushita Electric Industrial Co., Ltd. Solid-State Imaging Device
US7667171B2 (en) 2004-07-06 2010-02-23 Panasonic Corporation Solid-state imaging device
US7733393B2 (en) 2005-05-19 2010-06-08 Casio Computer Co., Ltd. Digital camera comprising smear removal function
US20060274173A1 (en) * 2005-05-19 2006-12-07 Casio Computer Co., Ltd. Digital camera comprising smear removal function
US20100103293A1 (en) * 2005-05-19 2010-04-29 Casio Computer Co., Ltd. Digital camera comprising smear removal function
WO2006123828A1 (en) * 2005-05-19 2006-11-23 Casio Computer Co., Ltd. Digital camera comprising smear removal function
CN101180869B (zh) * 2005-05-19 2011-05-25 卡西欧计算机株式会社 具有拖尾消除功能的数字摄像机
US8314864B2 (en) 2005-05-19 2012-11-20 Casio Computer Co., Ltd. Digital camera comprising smear removal function
US20080165262A1 (en) * 2006-12-12 2008-07-10 Axis Ab Method for capturing image data
US20090167916A1 (en) * 2007-12-26 2009-07-02 Samsung Techwin Co., Ltd. Imaging apparatus and methods, and storing medium having computer program to perform the methods
US8031245B2 (en) * 2007-12-26 2011-10-04 Samsung Electronics Co., Ltd. Imaging apparatus and methods, and storing medium having computer program to perform the methods
US20100014775A1 (en) * 2008-07-16 2010-01-21 Canon Kabushiki Kaisha Image processing apparatus and image processing method
EP2146306A3 (en) * 2008-07-16 2013-02-20 Canon Kabushiki Kaisha Image processing apparatus and image processing method
US8401328B2 (en) 2008-07-16 2013-03-19 Canon Kabushiki Kaisha Image processing apparatus and image processing method

Also Published As

Publication number Publication date
DE3442647C2 (enrdf_load_stackoverflow) 1992-07-16
DE3442647A1 (de) 1985-05-30
GB2151105A (en) 1985-07-10
GB8428276D0 (en) 1984-12-19
GB2151105B (en) 1987-02-25
JPS60112376A (ja) 1985-06-18

Similar Documents

Publication Publication Date Title
US5331421A (en) Solid state image pickup apparatus
US5771070A (en) Solid state image pickup apparatus removing noise from the photoelectric converted signal
EP0720360B1 (en) An electronic camera with rapid automatic focus of an image upon an image sensor
US5737016A (en) Solid state image pickup apparatus for reducing noise
KR100414322B1 (ko) 고속모드를갖는디지탈비디오카메라
US4980771A (en) Imaging device and imaging apparatus including the imaging device
US4547807A (en) CCD Imager
US4189751A (en) Solid state television camera with defect compensation to reduce noise
US4490744A (en) Smear reduction technique for CCD field-transfer imager system
US5363137A (en) Focus adjusting apparatus which reads a selected portion of an image pickup plane
JPH0335870B2 (enrdf_load_stackoverflow)
NL8201745A (nl) Beeldopneeminrichting van het "solid state"-type.
US5777670A (en) Device for controlling transfer in a CCD-type imaging device
US5216511A (en) Imaging device with elimination of dark current
US5311320A (en) Solid state image pickup apparatus
US5477265A (en) Device for controlling imaging device
US5883667A (en) Solid-state image pick-up device eliminating smear image component from video signal through real time control
US5631705A (en) Video camera having circuit for setting exposure compensation value
EP0547697B1 (en) Solid state imaging device and camera provided with such an imaging device
US5576762A (en) Solid-state image pickup device
US6700608B1 (en) Image pickup apparatus
US6339213B2 (en) Solid state imaging device and method for driving the same
JPH0831979B2 (ja) 像記録用カメラ及びその信号処理方法
JP2994158B2 (ja) 固体撮像装置
US5555020A (en) Solid-state imaging apparatus

Legal Events

Date Code Title Description
AS Assignment

Owner name: SANYO ELECTRIC CO., LTD. 18, KEIHAN-HONDORI 2-COME

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNORS:MITANI, NOBUHIRO;FURUSAWA, TOSHIHIRO;REEL/FRAME:004337/0446

Effective date: 19841024

Owner name: SANYO ELECTRIC CO., LTD.,JAPAN

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:MITANI, NOBUHIRO;FURUSAWA, TOSHIHIRO;REEL/FRAME:004337/0446

Effective date: 19841024

STCF Information on status: patent grant

Free format text: PATENTED CASE

FPAY Fee payment

Year of fee payment: 4

FPAY Fee payment

Year of fee payment: 8

FPAY Fee payment

Year of fee payment: 12